Experimental Researches in Electricity. 347 



arranged and approximated both in air and in an exhausted 

 receiver, from a battery of 140 pairs of plates, which was 

 capable of deflecting the gold leaf electrometer about one- 

 third of an inch, no such indications could by any possibility 

 be obtained. In this result, however, there was found to be 

 no discordance between ordinary and voltaic electricity, since 

 when a Leyden jar was charged so as to produce a deflec- 

 tion of the electrometer equal to that mentioned above, the 

 points were found equally unable to discharge it with such 

 effect as to produce either magnetic or chemical effects. 

 Hence then, the influence of points proves in so far identity, 

 instead of difference, between common and voltaic electrici- 

 ties. 



Heated air was then employed as a means of discharging 

 the electricity of the battery, and the clearest evidence of 

 the passage of the fluid between the two platinum points 

 terminating the apparatus employed, was obtained, both by 

 chemical decomposition and magnetic influence. The in- 

 stantaneous charging of a Leyden jar, by the application to 

 a battery is another decisive proof of the tension of voltaic 

 electricity. 



In motion, the electricity of the battery produces all the 

 effects mentioned in the standard of comparison, and its 

 powers of evolving heat and magnetism, of producing che- 

 mical decomposition, physiological effects, and a brilliant 

 spark — the most brilliant indeed that man can obtain, by 

 artificial means — are familiar to all. It satisfies therefore 

 in the most complete manner, the various conditions of the 

 comparison. 



Before proceeding to the examination of ordinary electri- 

 city, Faraday considers it necessary to define certain expres- 

 sions, which subsequently come much into use. These are 

 first, the term current, by which he understands any thing 

 progressive, whether it be a fluid of electricity, or two fluids 

 moving in opposite directions, or merely vibrations ; or speak- 



